For a number of years, airplanes have been used for spraying chemicals onto land. For example, airplanes have been used for spraying fertilizer, insecticides, herbicides, and the like on farm land. Also, airplanes have been used for spraying insecticides and herbicides on grazing land and on forest land to control the tussock moth.
With the spraying of these chemicals onto land, it is necessary for the airplane pilot to know where the chemicals have been sprayed and where the chemicals have not been sprayed. To know the demarcation between these two areas, it is necessary to have an indicator. A satisfactory indicator is a drop marker which can be dropped from an airplane and which has an identifying portion or member which can be seen by the pilot in the airplane when the drop marker is on the ground or hanging from a tree in a forested area.
The drop marker should be, relatively, inexpensive--as a large number of drop markers are used by airplane pilots in the spraying of chemicals onto the farm land, range land, and forests.
PATENT NUMBER INVENTOR ISSUE DATE TITLE __________________________________________________________________________ 1,564,152 J. M. Thomson Dec. 1, 1925 Sample Display Folder 1,798,052 F Addition Mar. 24, 1931 Warning Signal 1,805,002 F. Neumeyer May 12, 1931 Letters, Figures, . . . from Aircraft 1,985,678 L. T. Hand Dec. 25, 1934 Superfold Paper Tape 2,149,530 L. Loweth Mar. 7, 1939 Continuous . . . Record Assembly 2,183,540 D. H. Campbell et al Dec. 19, 1939 Target Towing Device 2,238,875 F. G. Manson Apr. 15, 1941 Aerial Trailer 2,134,987 N. N. Shorb Nov. 1, 1938 Method of Aerial Advertis- ing 2,349,984 R. K. Ostrander May 30, 1944 Toy 2,360,516 G. T. Schmidling Oct. 17, 1944 Phosphorescent Device 2,610,868 M. Flament Expanding folder . . . Manufacturing same 2,825,803 L. Newbrough Mar. 4, 1958 Crash . . . Indicator 2,949,094 F. H. Clothier Aug. 16, 1960 Visual Aircraft Finder 3,059,362 J. Scherotto Oct. 23, 1962 Collapsible . . . Device 3,280,549 Jui-Cheng Hsu Oct. 25, 1966 Release Mechanism . . . Expandable Cartridge 3,428,019 D. Tillay et al Feb. 18, 1969 Drop Marker 3,470,846 D. Tillay et al Oct. 7, 1969 Marking the line of Flight of an Aircraft __________________________________________________________________________